7104

• UCREFRP Catalog Number: 7104
• Author: Green, B. and M. Butler.
• Title: Analysis of Channel Maintenance and Flushing Flows in the Colorado River at the Palisade Habitat Site ‎(Appendix B)‎.
• USFW Year: 1987.
• USFW - Doc Type: \
• Copyright Material: NO

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APPENDIX B

FINAL
_July 7, 1987

Analysis of Channel Maintenance and
Flushing Flows in the Colorado River
at the Palisade Habitat Site.

Introduction

The Fish and Wildlife Service identified a channel maintenance flow
requirement for the Palisade habitat site of 14,000 cfs in its
March 10, 1987 draft report "Palisades Habitat Analysis Using the
Instream Flow Incremental Methodology." The Denver Water
Department reviewed the March 10 report, and presented comments in
a draft letter to John Spinks dated March 23, 1987. The written
comments were followed by a meeting on April 15, 1987, between
technical staffs for the Fish and Wildlife Service and the Denver
Water Department, plus engineering consultants for the Department.

The basic conclusions presented by Denver and its consultants are
contained on page 4.3 of a report by Simons,Li and Associates
dated May 5, 1983, entitled "Thermal and Sediment Transport
Analyses Associated with the GeC Intake:"

The combination of flow regulation from water resources
projects, geologic controls, and the gravel, cobble and
i boulder bed nature of the stream results in producing a
channel which is extremely stable over engineering type
time frame (on the order of 100 years). The numerous
geologic controls provide points at which both the al-
ignment and profile of the Colorado River are control-
led and will not be impacted by upstream development.
. The gravel, cobble and boulder bed nature of most of
the river creates a condition in which the river bed is
armored and cannot degrade. The upstream water resource
development has increased the effectiveness of channel
armoring by reducing the frequency of flows capable of
disrupting the armor layer. The high discharges that
account for the majority of changes in the system have
been reduced in frequency. Thus, the Colorado River is
now flowing in a somewhat oversized channel in relation
to its present hydrology.

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